This invention relates to an improved scroll switch and particularly a scroll switch that is capable of assembling and disassembling rapidly.
Many of the presently available mouse devices, notebook computers or handheld computers and keyboards have one or more roller means for users to control zoom in and zoom out of the viewing window or switching of the viewing pages. The means of using roller rotation to activate an encoded signal output may be seen as a scroll switch for switching window pages.
FIG. 1 illustrates a conventional scroll switch which generally includes a casing 9 and an encoder mechanism 2. The encoder mechanism 2 consists of a body 3, a press element 5, a rotary element 6 and a contact element 7. The press element 5, rotary element 6 and contact element 7 are assembled in the body 3, then the casing 9 is fastened to the body 3 at one side thereof. The casing 9 has arms 91 gripping the body 3 at two outer sides and bent for holding the press element 5, rotary element 6 and contact element 7 securely in the body 3. When in use, it can generate an encoded signal output under the driving of the rotating roller 10 to control the page switching of the windows.
As the arms 91 is bent to grip the body 3 at the outer sides, the bending of the arms 91 is a labor intensive operation and takes a lot of time. Once assembled, if there is malfunction or breakdown happened to the encoder mechanism 2, the arms 91 have to be bent in opposite direction for disassembling the casing 9 to replace the damaged parts and bent again for restoring the mechanism to operative condition. After repetitive bending, the arms 91 tend to lose the mechanical strength and unable to hold the casing 9 tightly, and may result in the press element 5, rotary element 6 and contact element 7 not being held securely in the casing 9. As a result, the scroll switch will have poor contact or generate fault encoding signal output and create mistaken page switching.
It also can happen that the arms 91 will be deformed or ruptured and broken after repetitive bending and result in damage of the casing 9. This will increase the cost.
In view of aforesaid disadvantages, it is therefore an object of this invention to provide an improved fastening means that enables the scroll switch be assembled and disassembled rapidly for increasing production yield.
Another object of this invention is to save assembly process and time, and to reduce production cost.
To attain the foregoing objects, the scroll switch according to this invention includes a casing which has a housing chamber bordered by two walls at two sides. Each wall has a bore and a fastening snap aperture located below the bore. The encoder mechanism may be disposed in the housing chamber and engage with the snap aperture through a snap stub formed on a cap of the encoder mechanism. Thus the encoder mechanism may be fastened to the casing rapidly. Likewise, the encoder mechanism may be disassembled quickly for repairs and maintenance.